Notice bibliographique
Résumé
Scots Bay Beach is one of the largest bay head gravel barrier beaches within the inner Bay of Fundy that are exposed to waves generated along the length of the bay. It is a 60 m wide transgressive barrier with a limited coarse sediment supply. Less than 3 m of coarse sediment overlie buried marsh clay which is often exposed along the mid-lower beach face. The steep sloping beach face is fronted by an 800 m wide, intertidal flat. The beach is backed by wave washover and/or dune deposits and a 100 to 200 m wide salt marsh. The marsh is drained by tidal creeks which enter the sea through an outlet near the centre of the beach. Terrestial seismic reflection and refraction surveys, vibracoring and marsh boreholes reveal a complex coastal stratigraphy. Landward of the salt marsh about 18 m of lower velocity sediment interpreted as glaciofluvial or raised beach deposits overlie bedrock. Thickest marsh deposits cored were 8.8 m, but core penetration was limited because of abundant driftwood buried in the marsh. The intertidal flats, within 200 m of the beach face, consisted of wave reworked sands, granules and pebbles over a wedge of salt marsh clay and an intermediate velocity deposit interpreted as a diamicton. It extends to bedrock which slopes steeply westward to a depth of 19 m beneath the tidal flat. Barrier beach positions at 1000 years (1ka), 2000 and 3000 years BP (radiocarbon years (14C years) before present where present is 1950) were reconstructed using paleo-marsh elevations, sea level curves and a radiocarbon date of 3160 ± 50 BP from a vibracore sample collected within 150 m of the present beach face. The beach at 1 ka BP was no closer than 115 m from the present beach face and the 3 ka beach was a minimum of 150 m seaward and probably more than 300 m seaward of the present beach face (using a beach migration rate of 0.1 m /a). Scattered boulders and a thin bed of well-rounded polished granules and fine pebbles over truncated marsh deposits observed beneath the intertidal flat may represent a sedimentary facies of a transgressive macro-tidal barrier beach. The barrier beach can be divided into seven distinct cross-shore zones between the intertidal flats and the back barrier marsh. Driftwood accumulation is an important factor controlling beach crest sedimentation and stability, particularly along the central and northern barrier where backshore dunes are absent. Rates of landward beach migration between 1945 and 1987 were documented by comparing repetitive air photography. The landward edge of the barrier migrated 22 to 47 m during the 42 years; a rate of 0.5 to 1.1 m/a, most along the central part of the barrier and least toward its north and south ends. Since 1984 shore migration was documented using repetitive cross-shore surveys at three locations. The landward edge of the northern barrier migrated 12 m and the beach crest at three sites has migrated 12 to 18 m during the 24 years since 1984, an average rate of 0.5 to 0.8 m/a. Rates of landward beach migration have been similar since the 1940s and higher than the suggested paleo-rates. Accelerated migration may have been triggered by the loss of sediment reserves by beach mining and the loss of wharf structures between the late 1940s and late 1950s. The beach crest can experience short term building phases and remain fairly stable for several years, e.g. 1986-1991. The beach crest is pushed landward episodically, only when westerly storms coincide with higher high tides e.g. Feb. 1976 and Oct. 2015, resulting in sheet wave overwash of the entire barrier. Storm wave run-up can exceed the elevation of the present beach crest of 7.6 m and the maximum flood level can reach 6.4 m (Geodetic Datum) along the back edge of the marsh. It was observed that flooding of Scots Bay Beach and the access road to the beach occurred after water levels reached 8.5 m or higher (Chart Datum) at Saint John, N. B., e.g. Oct. 30, 2015. Therefore, in the future, during periods of sustained strong westerly winds, water levels recorded at the tide gauge in Saint John, New Brunswick could provide a warning of potential flooding at Scots Bay Beach. Based upon rates of landward beach migration since 1984, much of the marsh, particularly behind the northern barrier, will be squeezed out and disappear by 2100, as the beach migrates and builds against the higher backshore.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».